Streaming Media Transmission Control Research And Realization

With the popularization of wide band and development of digital coding, there are more and more applications, such as long-distance education, video no demand and videoconference, supported by stream-media technology. Congestion control, especially congestion control of stream-media, has been a hot issue of Internet development, and it will play an important role in the popularization of stream-media.This paper starts with an introduction, which explains the background of TCP -friendly rate control mechanism. Afterword, congestion control mechanism of unicast and multicast was analysed. Then, some representive unicast and multicast congeston control protocols was presented with their advantage and shortcomes both.This paper gave emphasis to congestion control mechanism for stream media transport, and proposed a model-based congestion control algorithm for real-time stream unicast, CRFCC algorithm (Congestion Rate Feedback Congestion Control) based on congestion rate feedback. The Simulation results indicated that CRFCC shows good TCP-friendliness and smoothness.In addition, the paper studied TCP-friendly multicast congestion control TFMCC and found some defects in TFMCC and analyzed academic reasons.Finally, a video and audio transport system, based on RTP and DirectShow, was realized. It achieved video and audio capture, coding, network transmission by unicast and multicast, decoding and replaying. And the test result of unicast with CRFCC shows that the algorithm achieve the intending effect.